base fare

American Airlines’ roll-out of a new bundled fare structure this week has created some confusion among frequent fliers about what the change means to the way they book tickets. They have nothing to worry about — at least for now. American is not changing the decades-long practice of how fares are published on an airline tariff, and fears of a lack of transparency are misplaced.

You can still see in which booking class your ticket will be issued, though it’s indeed a bit confusing how exactly one would know the difference between the three new fare types by looking at that booking class, which could be the same for all three fares. So let’s break all this down and try to make sense of it.

First, what has American changed? It has bundled products and services that airlines have been unbundling for a few years, though some of those extras like certain seats are still sold separately. When you search domestic fares in the contiguous 48 states on its website, you now get three tabs: lowest fare, refundable (both coach) and Business/First Class. The default tab is lowest fare. In that category, there are three types of fares, as shown below for a one-way trip from Washington to Los Angeles…

There have been hundreds of media stories in the last week about the Delta Airlines website “glitch” that overcharged members of its loyalty program on airfare across the board, but what none of those stories tells us is how to recognize and fight such airline practices — whether deliberate or accidental.

As this column has pointed out before, airlines try to overcharge customers all the time, and a decade ago, I used to fall for some of those tricks. That’s why I decided to learn the system — and that’s one of the reasons I wrote “Decoding Air Travel.” If you ever needed proof that knowledge means power, look no farther.

So how could you have known that the Delta website was charging you more than the lowest available fare? First, you have to understand what an airline tariff is: A list of all published base fares on a certain route, along with their rules and permitted routing — they carry a code corresponding to a letter of the alphabet. The second thing is the flight inventory, or the number of seats in each booking class made available on a certain flight…